The purpose of this project is to explore the great variety and abundance of the marine environment for molecular models of neurobiology. In particular it was designed to investigate species or phenomena which display an amplification or simiplification of human physiologic or pathologic metabolism. Further studies were conducted on the neurotoxic effects of several pesticides in tissue preparations derived from lobster axons and from mammalian brains. Comparative studies in a variety of species dealt with the role of divalent cation in the activation of membrane ATPases. It was found that Mn++ plays a dominate role in ATPase activation in particular in the lower (invertebrate) species. In mammalian brains Mn++ appears to be the most active cation for the activation of ATPases in synaptic vesicles.